Method and apparatus for evacuating sealed chambers



Dec. 12, 1967 l. w. SIMONS A 3, 5 ,446

METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Filed Dec. 29, 19665 Sheets-Sheet l FIG.1

INVENTOR IRA W. SIMONS ATTORNEYS Dec. 12, 1967 w. SIMONS 3,357,446

METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Filed Dec. 29, 19665 Sheets-Sheet INVENTOR IRA w. SIMONS ATTORNEYS FIG.4

Dec. 12, 1967 w. SIMONS METHOD AND APPARATUS FOR EVACUATIN Filed Dec.29, 1966 G SEALED CHAMBERS I 5 Sheets-Sheet 5 FIG.5

INVENTOR.

IRA W. SIMONS ATTORNEYS I. W. SIMONS METHOD AND APPARATUS FOR EVACUATINGSEALED CHAMBERS Dec. 12, 1967 5 Sheets-Sheet 4 Filed Dec. 29, 1966 R mwe V M mm 0 H W A m I l 6 H4 FIGS ATTORNEYS I. W. SIMONS Dec. 12, 1967METHOD AND APPARATUS FOR EVACUATING SEALED CHAMBERS Filed Dec. 29, 19665 Sheets-Sheet 5 FIG. 10

INVENTOR.

IRA W. SIMONS UM Miami ATTORNEYS United States Patent 3,357,446 METHODAND APPARATUS FOR EVACUATING SEALED CHAMBERS Ira W. Simons, Columbus,Ohio, assignor to Cryo-Vac,

Inc., Columbus, Ohio, a corporation of Ohio Filed Dec. 29, 1966, Ser.No. 605,904 11 Claims. (Cl. 137322) The present invention relates tomethod and apparatus for use in evacuating sealed chambers such as theevacuated insulating spaces provided around conduits or vessels forcontaining cryogenic gases such as liquid nitrogen and the like.

This application is a continuation-in-part of my c0- pendingapplications Ser. No. 402,300, Ser. No. 402,299, and Ser. No. 402,298,all filed on Oct. 7, 1964 and all now abandoned.

In general, the valve mechanism of the present invention comprises afixed housing portion for parmanent attachment to the wall of thechamber to be evacuated and a valve means removably mounted in the fixedhousing portion which provides means for releasing air from the sealedchamber to a pump apparatus.

The valve means includes a valve element that is normally biased closedagainst a valve seat and the only time it is open is when subjected tosuction from a vacuum pump during the actual evacuation of the chamber.The valve element is also self-closing after evacuation to seal out airfrom the environment.

The valve means also includes a removable cover which is mountable on ashoulder of the fixed housing portion after evacuation of the chamberwhich cover includes a Warning device to provide visual detection of theleakage of cryogenic gas from the conduit or vessel through theevacuated chamber to the environment.

As another aspect of the present invention the same shoulder of thefixed housing portion upon which the valve cover is mounted can also beadapted to function as a mount for a pump attaching apparatus in theform of an outer removable housing when evacuation of the sealed chamberis desired. It will be understood that the valve cover is replaced bymounting it on the same shoulder when the pump attaching apparatus isremoved after evacuation.

When the outer housing portion is afiixed to the inner housing portionfor the evacuation period it provides a sealed chamber around the abovementioned valve assembly which sealed chamber forms a passage thatconnects the valve assembly and outlet port for the chamber with thevacuum pump.

In accordance with the present invention the above mentioned pumpattaching means or outer housing portion includes a valve assemblylifting mechanism which provides means for the operator to lift theabove mentioned valve assembly outwardly but within the sealed housingportion to an evacuating position wherein the valve assembly is notinterposed in the flow of air between the outlet port of the sealedchamber and the inlet of the conduit leading to the vacuum pump.

The valve assembly may be locked in this evacuation position duringactual evacuation by means of a positive locking device provided in thehandle portion of the lifting mechanism.

It will now be understood that with the valve assembly moved to theouter no-restricting position the apparatus is adapted to effect Whatmay be termed high conductance pumping, that is to say the valvecomponents are actually removed from the air flow path while the sealedchamber is being evacuated. This results in highly efficient pumping ofair at low pressure under which conditions the air molecules areparticularly impeded in their 3,357,446 Patented Dec. 12, 1967 "ice flowby passage restrictions normally present in the form of valvecomponents.

After evacuation of the chamber, the lifting mechanism is unlocked bythe operator and used to return the valve assembly to its normal innershut-off position wherein it prevents the ingress of environmental airto the evacuated chamber. Then the lifting mechanism may be removedcompletely.

It is, therefore, an object of the present invention to provide an novelvalve apparatus for use in evacuating sealed chambers and is adapted forstraight through high conductance pumping during the evacuation cyclewherein the valve assembly may be positively locked in the evacuationposition.

It is another object of the present invention to provide a novel valveapparatus, for use in evacuating sealed chambers, having a handleportion which functions not only as a handle, but further as a positivelocking means to hold the valve assembly in the evacuation position.

It is another object of the present invention to provide a valvemechanism for use in evacuating sealed chambers and is adapted toprovide a visual warning for rapid detection of leakage of cryogenicgases through the valve means.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of embodiment of the invention isclearly shown.

In the drawings:

FIG. 1 is a partial side elevational view, partially in section, showingan inner housing and valve means constructed in accordance with thepresent invention;

FIG. 2 is a top elevational view of the housing and valve means of FIG.1;

FIG. 3 is a side sectional view of the housing and valve means of FIG.1, the section being taken along the line 3 3 of FIG. 2;

FIG. 4 is a side elevational view, partially in section, of a cover andblow-out disk assembly comprising a portion of the valve apparatus ofFIG. 1;

FIG. 5 is a side sectional view of a pump attaching means and valvemeans lift mechanism for use with the valve means of the precedingfigures, the section being taken along the lines 5-5 of FIG. .6;

FIG. 6 is a top elevational view of the outer housing portion and valvemeans lift mechanism of FIG. 5;

FIG. 7 is a partial side view, partially in section, illustrating thepump attaching mechanism of FIGS. 5 and 6 in mounted relationship on theinner housing portion of FIGS. 14, the section being taken along theline 5-5 of FIG. 6;

FIGS. 8 and 9 are sectional views showing a lug and groove constructioncomprising a portion of the valve means lift mechanism of the presentinvention, the sections being taken along the line 8, 9-8, 9;

FIG. 10 is a side view, partially in section, showing the valve means ofthe preceding figures after it has been lifted by the valve means liftmechanism to a non-restricting evacuating position;

Referring in detail to the drawings, FIG. 1 through 4 illustrate apreferred embodiment of a valve apparatus for use in evacuating sealedchambers.

As an example, the valve apparatus indicated generally at 20 includes aninner housing portion 22 that is permanently secured to an outer wall orvacuum jacket 24 that forms an evacuated insulating space 26 around aconduit 28 which is used for conducting a flow of cryogenic gas such asliquid hydrogen, liquid nitrogen, or the like. It should be pointed outthat inner housing portion 22 is extended through an opening 30 andsecurely '2 a mounted on jacket 24 at a scaled junction formed by a weld32.

As seen in FIGS. 1 and 4, valve apparatus 20 further includes aremovable cover 34 that comprises an annular inner wall surface 36 whichis adapted to slip snuggl over an outer annular shoulder means 38 oninner housing portion 22, the latter being illustrated in FIG. 3.

Continuing to refer to FIGS. 3 and 4, an annular resilient seal 40 ismounted in an annular groove 42 in shoulder means 38 and the innersurface 36, FIG. 4, of valve cover 34 is provided with an annular groove44 that receives resilient seal 40 when the cover is slipped down overinner housing portion 22.

Referring particularly to FIGS. 3, 7 and 10, it should next be explainedthat inner housing portion 22 supports a removable valve means indicatedgenerally at 46 which means is joined to the inner housing portion at athreaded junction 48.

As best seen in FIG. 3, valve means 46 comprises an annular valvehousing wall 50 in which is mounted a movable valve element 52 that isbiased downwardly against a seat portion 54 formed on the upper end ofthe lower housing portion 22.

Movable valve element 52 is biased downwardly by a compression spring 56interposed between the upper surface 58 of the valve element and a snapring 60 removably disposed in a groove 62 formed in the inner surface ofhousing wall 50.

it should be pointed out that when valve means 46 is unscrewed andlifted away from lower housing portion 22 from the position of FIG. 7 tothe position of FIG. 10, movable valve element 52 is retained within thevalve housing wall 59 by the inwardly extending annular projection 64which underlies an outwardly extending projection 66 on valve element52.

Reference is next made to FIGS. through which illustrate a vacuum pumpconnecting means and valve means lift apparatus indicated generally at 70.

At the outset it should be mentioned that the apparatus 70 is mounted oninner housing portion 22, as seen in FIGS. 7 and 10, only whileinsulating space 26, FIG. 1, is being evacuated by a vacuum pump. Afterthe evacuation cycle, apparatus 70, FIGS. 5, 7, and 10, is removed fromthe inner housing portion and cover 34 of FIGS. 1 and 4 is replaced overthe valve means. The same pump attaching means is then attached to othervalve assemblies for use in evacuating other chambers.

Referring particularly to FIGS. 5 through 7, the pump connecting meansincludes an outer housing portion 72 provided with an inner annularmounting surface 74 adapted to slip snuggly over shoulder means 38 andresilient seal 40 on the previously described inner housing portion 22.

Referring next to FIGS. 5 through 10 pump attaching means 70 includes anoutlet conduit 76 that communicates with the inlet of a vacuum pump, notillustrated, and an inner sealed chamber 78 that forms an outer passageportion that communicates with an inner passage portion through innerhousing portion 22, FIG. 3.

In general, it should now be explained that with the pump attachingmeans 70 in place on inner housing portion 22, as seen in FIG. 7, whenthe vacuum pump is operated air from within the insulating space 26,FIG. 1, is drawn through inner passage portion 8%, FIG. 3, and theannular space around movable valve element 52 when the latter is raisedfrom its seat 54 by the suction of the pump. The air then passes throughvalve housing outlet ports 82, FIG. 7, and thence outwardly throughconduit 76 to the vacuum pump.

When valve means 46 is lifted to the outer non-restricting position ofFIG. 10 then air is exhausted from insulating space 26, PEG. 1, via theinner passage portion 80 of inner housing portion 22, FIG. 3, thence,directly through outer passage portion 78 of outer housing portion 72and exhaust conduit 76 to the vacuum pump without passing through therelatively restricted path formed by the lifted and open movable valveelement 52 and the relatively restricted outlet ports 82.

The apparatus for lifting valve means 46 from the seated shut-offposition of FIG. 7 to the lifted non-restricting position of FIG. 10will next be described in detail. Such lift mechanism comprises a liftrod 86 slideably extended through a bore 88 through the top of outercasing 72 and also through sealing elements 90 and 92 and a sealretaining and compressing nut 94.

The lower end of lift rod 86 includes a first latching meansin the formof a latch member 96 secured against rotation on the lower end of rod 86by a pin 98 extended through a hole 100 in the end of the rod and theholes 102 in the latch member 96. The first latching means in the formof latch element 96, just described, is adapted to detachably engage asecond latching means formed by two arcuate grooves 104, FIGS. 3, 8, and9, formed in the upper inner surface of valve housing 50.

With continued reference to FIGS. 5, 8, and 9, the latch member 96 onthe lower end of lift rod 86 includes radially outwardly extendingprojections 106 that can be inserted into the open ends 108 of arcuateslots 104 by lowering lift rod 86 when rotated to the position of FIG. 8wherein projections 106 can move downwardly into slots 110.

With the projections 106 in slots 110, and in confronting relationshipwith the open ends 108 of arcuate grooves 104, a handle 112 on the upperend of lift rod 86 is rotated in a clockwise direction as indicated bythe arrow in FIG. 8 to thereby rotate latch element 96 to a positionwherein projections 106 engage the closed ends 114 of the arcuategrooves 104.

With the two latching mechanisms engaged as shown in FIG. 9 rotation ofhandle 112 Serves to unscrew valve assembly 46 from inner housingportion 22 at the previously mentioned threaded junction 48.

When the threads are disengaged the operator lifts rod 86 and valveassembly 46 from the normal shut-off position of FIG. 7 to thenon-restricting evacuating position of FIG. 10, the vacuum pump is thenstarted whereby the air is exhausted from insulating space 26 in themanner previously described.

It should be pointed out that while valve apparatus 46 is in thenon-restricting position during the evacuation period handle 112 ispivoted about a central pivot pin 113, in the direction of arrow in FIG.10, to cause a groove 122, FIG. 5, in the bottom of handle 112 to alignwith rod 86. It will be understood that the right end 124 of handle 112will then overlie packing retaining nut 94 and prevent lift rod 86 andvalve means 46 from moving into the lower position where it wouldrestrict flow through outer housing passage portion 78.

After the insulating space 26 of FIG. 1 has been evacuated handle 112 ismanipulated to lower valve means 46 back into mounted engagement withhousing portion 22 at threaded junction .48 and the handle is thenrotated to screw valve means 46 back into mounted engagement with outerhousing portion 22 as seen in FIG. 3.

Rod 86 is next lifted to remove projections 106 out of slots 110 andpump connecting means 70 is next removed from its seat on shoulder means38 of the inner housing portion.

Cover 34, FIG. 4, is next replaced on shoulder means 38 with the annularresilient seal 40 on housing portion 22 disposed in annular groove 44 inthe cover.

With particular reference to FIG. 4, the top of cover 34 is providedwith a blow-out disk which may be formed of mylar plastic sheet having aten thousandths of an inch thickness or other suitable material. Disk130 is mounted between an inturned flange 132 and a snap ring 134mounted in a groove 136 formed in the inner surface of a side wall 138of cover 34.

The purpose of blow-out disk 130 is to provide a visual indicator in theevent there is leakage from liquified gas conduit'28, FIG. 1, intoinsulating space 26. If this occurs there is a rapid build up inpressure in insulating space 26, due to heating of the cryogenic gaswith a resulting rapid build up in preessure which will blow movablevalve element 52 off its seat and blow-out disk 130 outwardly from itsmounted position on cover 34. With disk 130 blown out, an inspectorcould readily visually determine that leakage has occured in the system.

While the form of embodiment of the present invention as hereindisclosed constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follows.

1. A mechanism for use in evacuating sealed chambers comprising, incombination, a housing portion attached to i a wall of said sealedchamber to be evacuated and including a passage communicating With theinterior of said sealed chamber; valve means for said passage andremovably mounted on said housing portion; a cover portion for saidvalve means and removably mounted to said housing portion; and valvemeans lift apparatus removably attachable to said housing portion andincluding interengaging means for connection with said valve means, saidportion having sealing means for engagement with said cover andapparatus.

2. The steps in the method of evacuating sealed chambers which methodcomprises attaching a housing portion to the wall of a sealed chamberwith a passage in said housing portion including a passage and aremovable valve means for said passage; temporarily attaching a valvemeans lift apparatus to said housing portion, providing a seal on saidhousing portion in sealed relationship with said apparatus said liftapparatus including an outlet and interengaging means for connectionwith said valve means; attaching the inlet of a diffusion pump to saidoutlet; actuating said interengaging means to move said valve means andthereby clear a portion of said passage; operating said diffusion pumpto evacuate said sealed chamber; and actuating said interengaging meansto move said valve means to a closed position.

3. The steps in the method of evacuating sealed chambers which methodcomprises attaching a housing portion to the wall of a sealed chamberwith a passage in said housing portion including a passage and aremovable valve means for said passage; temporarily attaching a valvemeans lift apparatus to said housing portion, providing a seal on saidhousing portions in sealed relationship with said apparatus, said liftapparatus including an outlet and interengaging means for connectionwith said valve means; attaching the inlet of a diflusion pump to saidoutlet; actuating said interengaging means to move said valve means andthereby clear a portion of said passage; operating said diffusion pumpto evacuate said sealed chamber; actuating said interengaging means tomove said valve means to a closed position; and attaching a valve meanscover to said housing portion.

4. A mechanism for use in evacuating sealed chambers comprising, incombination, a housing portion for attachment to a wall of a sealedchamber and including a passage communicating with the interior of saidsealed chamber and a shoulder means; valve means for said passage andremovably mounted on said housing portion; a valve cover removablyattached to said shoulder means; and valve means lift apparatusremovably attachable to said shoulder means and including interengagingmeans for connection with said vaive means.

5. A mechanism for use in evacuating sealed chambers comprising ahousing portion for attachment to a wall of a sealed chamber, saidhousing portion including a passage communicating with the interior ofsaid sealed chamber; valve means removably mounted in said housingportion; and means forming a mounting shoulder on said housing portionfor removably sealably receiving a valve means lift apparatus thatincludes an outlet for sealed connection with a vacuum pump, whereby thepassage portion communicates With said outlet.

6. An apparatus for. use in evacuating sealed chambers comprising, incombination, a fixed housing portion for permanent attachment to a wallof a sealed chamber and including an inner passage portion communicatingwith the interior of said sealed chamber; a valve assembly removablymounted on an outer end of said fixed housing portion and including amovable valve element, spring means biasing said valve element inwardlytowards a valve seat, and a first latch means; a removable housingportion including an inner end mountable in sealed relationship on saidfixed housing portion and having an inlet communicating with said innerpassage portion and an outlet for connection with a vacuum pump; and alift rod extended through a hole in the wall of said removable portionand including an inner rod end provided with a second latch meansdetachably engageable with said first means and an outer rod endprovided with a handle portion having a position lock means for holdingsaid lift rod in a fixed position. i

7. An apparatus for evacuating sealed chambers comprising incombination, a fixed housing portion for permanent attachment to a wallof a sealed chamber and including an inner passage portion communicatingwith the interior of said sealed chamber; a valve assembly removablymounted on an outer end of said fixed housing portion and including amovable valve element, spring means biasing said valve element inwardlytowards a valve seat, and an inner wall surface provided with arcuatecircumferentially extending grooves; a removable housing portionincluding an inner end mountable in sealed relation ship on said fixedhousing portion and an outer passage portion having an inletcommunicating with said inner passage and an outlet for connection witha vacuum pump; and a lift rod extended through a hole in the wall ofsaid removable housing portion and including an inner rod end providedwith radially extending projections detachably engageable with saidarcuate grooves and an outer rod end provided with a handle portionhaving a position lock means for holding said lift rod in a fixedposition.

8. An apparatus for use in evacuating sealed chambers comprising, incombination, a fixed housing portion for permanent attachment to a Wallof a sealed chamber and including an inner passage portion communicatingwith the interior of said sealed chamber; a valve assembly removablymounted on an outer end of said fixed housing portion and including amovable valve element, spring means biasing said valve element inwardlytowards a valve seat, and a first latch means; a removable housingportion including an inner end mountable in sealed relationship on saidfixed housing portion and having an inlet communicating with said innerpassage portion and an outlet for connection with a vacuum pump; and alift rod extended through a hole in the Wall of said removable portionand including an inner rod end provided with a second latch meansdetachably engageable with said first latch means and an outer rod endprovided with a handle portion pivotable from a transverse position toan aligned position with said outer rod end for positive locking of saidlift rod.

9. An apparatus for evacuating sealed chambers comprising incombination, a fixed housing portion for per manent attachment to a wallof a sealed chamber and including an inner passage portion communicatingwith the interior of said sealed chamber; a valve assembly removablymounted on an outer end of said fixed housing portion and including amovable valve element, spring means biasing said valve element inwardlytowards a valve seat, and an inner wall surface provided with arcuatecircumferentially extending grooves; a removable housing portionincluding an inner end mountable in sealed relationship on said fixedhousing portion and an outer passage portion having an inletcommunicating with said inner passage. portion and an outlet for connectwith a vacuum pump; and a. lift rod extended through a hole in the wallof said removable portion and including an inner rod end provided withradially extending projections detachably engageable with said, arcuategrooves and an outer rod end provided with a handle portion pivotablefrom a. transverse position to an aligned position with said outer rodend for positive. locking of said lift rod.

10. An apparatus for evacuating sealed chambers comprising, incombination, a fixed housing portion for permanent attachment to a wallof. a, sealed chamber and including an inner passage portioncommunicating with the interior of said sealed chamber; a valve assemblyremovably mounted on an outer end of said fixed housing portion-v andincluding a movable valve element, spring means biasing said valveelement inwardly towards a valve seat, and a first latch means; aremovable housing portion including an inner end. mountable in. sealedrelationship on said fixer housing portion and an outer passage portionhaving an. inlet communicating with said inner passage portion and anoutlet for connection with a vacuum pump; and a lift rod extendedthrough a hole in the wall of said removable housing portion andincluding an inner rod end provided with a second latch means detachablyengageable with said first latch means and an outer rod end providedwith a handle portion.

11. An apparatus for evacuating sealed chambers comprising, incombination, a fixed housing portion for permanent attachment to a wallof a sealed chamber and including an inner passage portion communicatingwith the interior of said sealed, chamber; a valve assembly removablymounted on an outer end of said fixed housing portion and including amovable valve element, spring means biasing said valve element inwardlytowards a valve seat, and an inner wall surface provided with arcuatecircumferentially extending grooves; a removable housing portionincluding an inner end mountable in sealed relationship on said fixedhousing portion and an outer passage portion having an inletcommunicating with said inner passage portion and an outlet forconnection with a vacuum pump; and a lift rod extended through a hole inthe wall of said removable housing portion, and including an inner rodend provided with radially extending projections detachably engageablewith said arcuate grooves and an outer rod end provided with a handleportion.

References Cited I UNITED STATES PATENTS 1,422,342 7/1922 Darling et al.220-39 1,483,964 2/1924 Abramovitz- 137-319 2,463,052 3/1949 Petryl4l.65 2,881,788 4/1959 Johnson l3732l 3,019,809 2/1962 Ipsen et al.l37-340 3,146,005 8/1964 Peyton 138l48 HENRY T. KLINKIEK, PrimaryExaminer.

1. A MECHANISM FOR USE IN EVACUATING SEALED CHAMBERS COMPRISING, INCOMBINATION, A HOUSING PORTION ATTACHED TO A WALL OF SAID SEALED CHAMBERTO BE EVACUATED AND INCLUDING A PASSAGE COMMUNICATING WITH THE INTERIOROF SAID SEALED CHAMBER; VALVE MEANS FOR SAID PASSAGE AND REMOVABLYMOUNTED ON SAID HOUSING PORTION; A COVER PORTION FOR SAID VALVE MEANSAND REMOVABLY MOUNTED TO SAID HOUSING PORTION; AND VALVE MEANS LIFTAPPARATUS REMOVABLY AT